Synchrotrons for Structural Chemistry

Tony Ryan, University of Sheffield

Tony – So I study the structure of polymers, plastics and colloid suspensions. So one example might be the structure of molecules that make up a shampoo bottle and also the structure of the molecules that make up the shampoo.

Meera – and how do you set about looking into this?

Tony – Well we do various things in the labs, we synthesise special molecules, we synthesise molecules that we can label so we know where they are and then we use the synchrotron as a source of high-intensity x-ray beams that allows us either to penetrate deep into a sample, or to look at a sample on its surface as it is doing its stuff and we can work out where the atoms are and how the whole molecules are organised.

Meera – And so what’s your real aim here, so what are you actually trying to find out about the molecules?

Tony – So, if we take the example of a shampoo bottle, then we are wanting to know when the material was processed, how the stretching of the molecules affected the way they crystallised. So when you make a bottle, you take a liquid and essentially you blow a bubble in the liquid to a special shape, that’s the shape of the bottle, and the stretching and the cooling causes the polymer molecules to organise themselves so that they crystallise and we study the stretching and the cooling and the crystallisation by following what the molecules do, in real time, by x-ray scattering.

Meera – and what have been, perhaps, some of your key findings having monitored the molecules in this way?

Tony – Well we’ve just had a paper published that compares the crystallisation of synthetic polymers like polyethylene, with the crystallisation of silk, from a silk worm. By using the synchrotron and by using other techniques in the lab at home, we’ve been able to estimate the energy needed to do the processing and we find out that the silk worm uses about 10% of the energy that we use to process polyethylene to make a fibre. So silk worms are much better a making fibres than people.

Meera – So is the aim then to really find out a bit more about how the silk worm does this to reduce our energy needs, or usages?

Tony – So what we can do from what we’ve learned about how silk worms go about processing silk, we’ve learned that it’s a different mechanism to the mechanism that’s used in making fibres of synthetic polymers. So what we can do is look to mimic the silk worms’ method in engineering materials. What the synchrotron has allowed us to do is compare the energetic of the 2 processes; learn that one process is much less energy intensive than the other and now we understand both how and why it’s less energy intensive to try and replicate that methodology in synthetic materials. So it actually means going back to the molecular drawing board and doing synthetic chemistry again.

Meera – Could you perhaps give a bit of insight into an even wider range of areas of chemistry that the synchrotron can be used for and that benefits other scientists?

Tony – So my colleagues in the chemistry field use the synchrotron for many, many reasons. So they do spectroscopy that they can’t do anywhere else to see what the local environment of individual atoms are, how catalysts work, like the catalytic converter in your car, other colleagues use it to study the crystallisation of drugs. So you can separate polymorphs, different forms of drugs because drugs crystallise in different ways and if you have the wrong sort of crystals in a tablet, they don’t work. But they can even work out how proteins interact with each other, so how proteins interact with drugs using a different set of scattering techniques called macromolecular crystallography. So there’s a whole variety of different techniques, imaging techniques, spectroscopy techniques that chemists use to study many, many different aspects of science. Whether it be; how rain clouds form or how drugs are taken into the marketplace.

Meera – And I guess with the opening of the new beamlines, which you must know about as well being on the Board of Directors and so on, this just must increase as well as each beamline opens as well?

Tony – The new beamline proposals open new areas of science, so for example, parts of what we do in terms of molecular engineering have been transformed by the availability of microbeams. So you can look in very fine detail in large parts. You only need very small crystals to be able to solve the structure. So all the time the techniques ands the technology at the synchrotron are pushing the envelope of what we can do and that generates new scientific opportunities with it.

Meera – What will you be looking into next then? What will be your next use for the synchrotron for your own work?

Tony – Well I’m really interested in how we use catalysts to clean up the environment so I’ve been working with and artist on making catalytic clothes and so what we want to do is to stick tiny catalyst particles to peoples clothes so they can walk around and take out environmental pollution - to use people and their clothing as catalyst supports. But to do that we need to understand how the catalyst particles stick to fibres and so my next project at the synchrotron will be to understand this process of depositing nanoparticles on to fibres. And we’ll use both imaging and scattering techniques to do that.

Meera – That’s a really interesting idea and so if you can just get a certain percentage of the population to wear that, that could make quite a big difference.

Tony – Yes, it would actually have to be quite a large proportion of the population. Each person could take out about 3 grams of nitric oxide a day, which doesn’t sound like very much but once you have a million people doing it then they take out 3 tonnes of pollution a day and once you start to get those sorts of numbers of people involved then you can have a significant impact on the urban environment.

Meera – So how can people get involved with this and find out more?

Tony – So there’s a great website called www.catalytic-clothing.org and there’s been lots of social media activity around this. At some point we’re going to be doing a pop-up laundry and we may even run a pop-up laundry at Diamond.

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